The effects of human retinal and cortical pathology on visual evoked potentials is studied using patterns as stimuli. The evaluation of monocular versus binocular abnormalities is based on a nonlinear analytic method. As a first step, we established that the midline recording sites are useful for recording the true binocular VEP. In patients with glaucoma, interocular differences in the response to coarse flickering patterns correlate with field and disc changes, but not with visual acuity. The human VEP shows complementary changes using dopamine precursor and dopamine blocking agents.